Virginia Angerclass

Exploring as ecotypes of more than 280 grasses

Exploring new wild plant species of
economic importance and tolerant of harsh environmental conditions in arid
countries may be a viable option to improve forage yield.. The present study was
conducted during two consecutive years and aimed to investigate the nutritional
values of eleven selected wild fodder species, six annuals and five perennials.
Detailed analysis for the nutritional values during two different seasons, for
perennials and two different growth stages for annuals were presented. The
results showed that most studied plants own high nutritional values compared to
earlier studies on taxonomically related
species growing in different arid areas. The mean content of dry matter, ash,
crude protein and lipids were 27%. 13%, 14% and 3.5%, respectively. Neutral
detergent fiber, acid detergent fiber, lignin, cellulose and hemicellulose were
44%, 26.5 %6.2%, 20.2 and 13.7%, respectively. The studied species recorded 43
and 49 as mean percent’s in vitro dry matter disappearance for perennials and
annuals, respectively. In general, there were slightly differences between the
two years for both perennials and annual species and significant differences
between different seasons for perennials and between growth stages for annuals.
The study strongly recommends further detailed experimental studies on A.
graecizan, Boerhavia diffusa and Cymbopogon schoenanthus,
which showed more crude protein, low fiber
content and high IVDMD, as unconventional forage crops in arid lands.

Key words: Forage; Aridity; flora;
Saudi.

Introduction

Saudi Arabia Kingdom
completely is located in arid and semi-arid dry region (24.1631° N, 43.6021° E.),
with an annual rainfall ranging from zero to 100 mm/year and consider one of
the poorest nations in terms of natural renewable water resources (De Nicola et
al., 2015). Flora of Saudi Arabia contains most aridity tolerant plants in the
world and possesses a unique genetic diversity as ecotypes of more than 280
grasses and legumes (Rao, 2013). The richness of the native flora in the
western and southwestern region of Saudi Arabia in plant relatives of
cultivated crops and fodders presents a genetic diversity that must not be
ignored (Alsherif et al., 2013; Alsherif & Fadl, 2016; Rao, 2013). Grazing
of wild plants from the desert supplements the fundamental and the most conventional
source for livestock production in Saudi Arabia. Although the presence of many
animal resources estimated to be more than 16 million heads (Bakhashwain & Abusuwar,
2011), feeding and browsing resources for livestock are very low. The policy of
fodder production in the Kingdom estimated that rangeland produces about twenty
million tons, dry matter, of which only ten million tons are edible and handy for
livestock feed, enough for just 50% of the animal units in Saudi Arabia,
indicating the presence of a feed gap (Bakhashwain & Abusuwar, 2011).

Varieties of new resources need to
be tapped to fill the basic needs for food and fodder request of increasing
population pressure in light of limited available resources and food deficiency
(Di Virgilio et al., 2015; Naah & Guuroh, 2017). Wild nutritive species
cultivation expected to be important sources for the forage improvement
programs in arid lands because of their adaptation to harsh environmental
conditions, so they are expect to be important sources for the crop improvement
programs (Alsherif, 2009; Walker et al., 2014). Although the natural vegetation
of Saudi`s desert comprises considerable numbers of palatable species rich in
their nutritive values that may consider reliable natural resources for fodder
production (Alsherif et al., 2013),  few
studies have dealt with this subject (Bakhashwain et al., 2010), and it received
little attention. Therefore, the present study aimed to (1) explore some wild
fodders, which grow naturally in the prevailing environmental conditions increased
ruminant production in arid environment, (2) study the effects of season for
perennials and growth stage for annuals on their nutritional values.

Material and Methods

Study area

The study was carried out in Khulais
area, Western Saudi Arabia, which is located between 39° 15` and 40° E and
latitudes 22° and 22° 30` N; its elevation ranged between 5 and 35 m above sea
level (Fig. 1). The area characterized by hot arid desert type climate with
scarce rainfalls and an average annual temperature of 27.7°C. The relative
humidity ranges between a maximum of 57% during August and April, and a minimum
of 37% during May and June (Table 1). The area is only used for grazing animals,
it was divided into five sites to include the entire representative,
topographic and physiographic condition; all selected species grow naturally in
all these sites (Table 2). The vegetation of the studied area is a
characteristic type of the natural plant life of the arid land. It is formed
mainly of xerophytic shrubs and undershrubs, e.g. Leptadenia, Indigofera,
Lycium, tough grasses, like Panicum, and a few trees of different
height, e.g. Acacia. In rainy times, short-lived plants (annuals)
probably alter the desert from yellow color into a green (Appendix).

Soil samples and analyses

Five soil samples were collected from zero to 50 cm depth for every
site. Soil texture was detected via Bouyoucos hydrometer procedure. Soil water extracts
of 1:2.5 were prepared for determinations of soil pH using pH meter Model HI
8519, and electrical conductivity (soil salinity) using CMD 830 WPA
conductivity meter. Soluble chlorides, Sulphates, and bicarbonates were
determined according to Jackson (1962). Sodium and potassium cations were
estimated using flame photometer (Allen et al., 1986). While Calcium and
magnesium cations were determined using EDTA (0.01N) according to Jackson
(1962).

 Samples selection and collection

A wide survey was completed
throughout the period of January 2015 to December 2016. Eleven wild fodder
species, five perennials and six annuals, were selected according to its
palatability and Bedouin knowledge; it has a good reputation among animal
breeders and prefer them to other plants. The selected perennial species were
Ochradenus baccatus Del., Cadaba farinosa Frossk., Panicum
turgidum Forssk., Cymbopogon schoenanthus (L.) Spreng. and Pennisetum
divisum (J.F. Gmel.) Henrard, while the annual species were Boerhavia
diffusa L., Astragalus vogelii (Webb) Bornm., Convolvulus deserti
Hochst. & Steud., Amaranthus graecizan L., Gynandropsis gynandra
(L.) Briq.,Ann. And Indigofera hoschstettei Baker.

Ten fodder samples representing
different parts of the aerial shoot system (young shoot for perennials) were
harvested from each site for each season (for perennials) and for each growth
stage (for annuals) within their distribution in the field. In each year samples
collection was done from the different sites during two different seasons
(autumn and spring) for the perennials and at different two growth stages
(vegetative and fruiting stages) for annuals, then pooled together to form a
single composite sample, then air-dried and stored in glass bottles.

Chemical analysis

For chemical estimation, samples
were grind to push through one mm screen in a CyclotecTM 1093 Sample Mill (Foss
Companies, Hillerød, Denmark). Samples were analyzed for dry matter (oven-dried
at 60 ?C for 48 h), ash (# 924.05) and ether extracts (EE) (# 954.02) according
to Association of Official Analytical Chemists (AOAC) (1990). The crude protein
(CP) in the fodder samples was separated as proposed by Cornell Net
Carbohydrate and Protein System; CNCPS (Licitra et al., 1996). In vitro dry
matter disappearance (IVDMD) was determined by a modified two-stage Tilley and
Terry procedure (Galyean, 1997). Ash-free neutral detergent fiber (NDFom) was
determined without use of sodium sulphide or amylase according to Van Soest et
al. (1991). Acid detergent fiber (ADFom) was determined (# 973.18; AOAC, 1990)
and expressed exclusive of residual ash. Lignin (sa) was determined by
solubilization of cellulose with 720 g/kg sulphuric acid (Robertson and Van
Soest, 1981). Cellulose and hemicellulose were determined sequentially
according to procedures of Van Soest et al. (1991). Calcium was detected by
atomic absorption, Na and K by the flame emission spectrometer. Phosphorus and
magnesium were determined by spectrophotometer.

Statistical analysis

A minimum of ten observations was
pooled of five replicates for each species to calculate the average values and
standard errors. SPSS software was used to estimate the least significant
differences of variation among the means of plant parameters using one-way
analysis of variance.

Results

Nutritional value of the studied
species

The majority of the studied species
recorded high nutritive values and exhibited significant differences (P